(Minnesota Daily) – From 2007 to 2012, more than a quarter of southeastern Minnesota’s grassland disappeared as fertilized farmland expanded — a shift in land use that’s contaminating the region’s private drinking water wells.

The switch from grass to crops — a trend across the Midwest that’s spurred by rising crop prices — could lead to a 45 percent increase in the number of wells in the region contaminated with potentially dangerous nitrate, according to recently published University of Minnesota research.

Though the link between agriculture and water contamination is well established, said the study’s lead researcher, Bonnie Keeler of the University’s Institute on the Environment, the recent study of southeastern Minnesota is one of the first attempts to understand the cost of nitrate pollution.

“We know there’s some private benefits and income generated from converting grass to corn,” Keeler said, “but there’s much less information on the societal costs.”

For the 70 percent of Minnesotans who rely on groundwater for drinking and the 1 million people who drink from private wells, there are both financial burdens and health risks.

Excess nitrate in well water, a majority of which comes from agricultural fertilizers, is potentially dangerous for infants, according to the Minnesota Department of Health. Nitrate is also associated with some cancer risks, according to the paper published in late June in the journal Environmental Research Letters.

A majority of southeastern Minnesota residents depend on groundwater for drinking, Keeler said.

“Many households are unaware of nitrate contamination in their wells,” Keeler said. “If they decide to do something about it, they’re on their own.” [more]